It is known in the gasket art that a resilient material, such as rubber or other polymeric compound, may be interposed between two closing surfaces in order to seal any spaces between the surfaces. Such a seal is intended to make the opposed surfaces air and liquid tight. Such gaskets are often employed in the liquid container art, wherein it is desired to prevent contained liquid from escaping from the container during storage or transit.
Liquid container gaskets, such as those encountered in the beverage container art, are often tubular, washer-like rubber elements which are placed on the rim of the container to be closed and sealed. A lid is then placed onto the container and fastened thereto, such that the gasket is interposed between the container and its lid. It is also a common practice to cause the lid to engage the container with some force, such that the interposed resilient gasket is compressed to some degree. The compression of the gasket, in turn, causes a more positive seal to be effected between the container and its lid. The degree to which such gaskets are compressed is often determined by how tight the lid is fitted to the container. For instance, when the lid has screw threads adapted to engage threads on the container, more turns of the lid onto the threads of the container results in a tighter seal.
It has been found that when a filled liquid container is dropped, the corresponding build-up of pressure from within the container is often sufficient to cause the gasket to be ejected from its normal position between the container and its lid. This condition is referred to as a "blow-out" which could well lead to potentially hazardous results, especially if the contained liquid is toxic or if it is being held at a high temperature.
One solution in the art to the hazard of a blowout has been to incorporate a venting system into the container, and/or its lid, in order to equalize internal and external pressures. While some venting systems have proved to be quite effective in accomplishing this task, it has been found that they are often inadequate to handle pressure build-up associated with larger liquid containers, such as those containing from three to five gallons of liquid or more. With these larger types of liquid containers, the internal pressures developed when the containers are accidentally dropped are often so large that a vent system cannot compensate for the sudden increases in pressure. At such times, the pressure is then directly exerted against the container lid, urging it away from the container itself. It is at this time that the danger of a blow-out is the greatest. Gasket and gasketing systems heretofore known in the art have proven incapable of consistently compensating for pressure increases of this kind.
It is also desirable to provide liquid containers which are easy to use and which can be molded using current molding technology. Obtrusive clamps, bolts and the like, while they may provide for secured lid closings and hence a decrease in blow-out potential, are likely to defeat the purpose of the storage container.
Therefore, a need exists for a gasketing system for a liquid container which is unobtrusive and yet possessed of an ability to prevent a blow-out even in the case of high pressure increases on the inside of the liquid container.